Re: Super Boulder Dash Problems?

[dempson@actrix.gen.nz (David Empson)]

Galen Tatsuo Komatsu <gkomatsu@Hawaii.Edu> wrote:

>       I tried playing Boulder Dash (and BDII, it's the Electronic
> Arts re-release) the other night on my //c and ran into a rather
> annoying problem.  Whenever I tried running to the right, instead of
> doing that, Rockford would take a step, then stop, step, stop, step,
> stop...  making the game impossible to play on some screens.  Only
> observation about it I made was it tended to happen when a stage had
> background music playing.

Could be an adjustment problem with the joystick, so that it is not
returning values up to 255.

Another possibility (more likely) is that Boulder Dash uses its own
routine to read the joystick, and it is not locking out interrupts,
resulting in timeouts that appear to be too early.  Both the IIc and
IIgs may have interrupts going in the background, stealing CPU cycles.

Yet another problem on the IIgs would be trying to run the game in fast
mode.  This would cause the joystick readings to be too high, resulting
in the joystick behaving like it has shifted too far to the right.

(Neither of these problems occur if the standard firmware routine is
used to read the joystick, but this would prevent the game from doing
any animation while it is waiting for input.)

If the game is not copy-protected, you might be able to set up a
pre-boot which locks out interrupts before launching the game.  If the
game enables interrupts itself, you would need to patch out the
instruction which does this.

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand